The answer should be B.
Explanation: You had to used their formula are: A= atomic mass numbers= to numbers of protons+ a number of neutrons in the nucleus. Z= atomic number equal to number of protons in the nucleus. N= to a number of neutrons in the nucleus. And it gave us the answer is A=N+Z=14 is the right answer. Hope this helps! And thank you for posting your question at here on Brainly. And have a great day. -Charlie